Process of recovering iron oxide and other products from spent iron sludge



Lns v. BACQIE, mantras, new Janene.

.rnocns's or nncovnnms mom Ann ornnn rnonucrs snore eraser more m'o hrawingQ To all whom it. may concern 7 j Be'it known that 1, CHARLES V. Bacon", a citizen of the United States, residing Mahwah, county of Bergen, and State of mixture consisting essentially of ferrous and ferric sulfates, the reaction being, it is helieved, represented by the following equation: lron'sludge-ltfl,SO

The sulfates so obtained are then calcined for a sufiicient time at a sufficiently high temp perature to decompose the same into oxide and a gaseous mixture of fur dioxideand trioxid as represented sunstan- Application filed 53, 1920. Serial dtdfi'fio will exist as a coarse grained owder, during the calcination, which len s itself very readily to roasting and does not meltdown and accumulate onthe furnace lining as is' 1. The process which consists insubject- 5 New Jersey, have invented a new and use. the case when acid of but Be. or thereto ful Improvement in Processes of Recovering abouts is employed.

' Iron Oxide and Other Products from Spent By employing the foregoing process by" Iron Sludge, of which the following is which the concentration of the acid em-' specification.v ployed is such as to prevent the formation 0 This invention relates to a process of an aqueous paste from which it is not utilizing the'spent iron-sludge, commercially necessary to evaporate the excess water be known as aniline reduction sludge, reduct r fore calcination, it is possible to not only, sludge etc, which is obtained as a byprodas previously stated, avoid the injury to the not from the manufacture of aniline, intro furnace or retort and to the end product,

benzene, metaphenylene, met'aphenyldia but also to effect the economicalproduc-W and-such other products that yield a proo tion of the desired iron oxide in the form of which is usually magnetic and essenti a brilliant red pigment which can bereadily com rises free or combined oxide of i ground with oil and thereby produce anr y investigations have led to the excellent oil paint therefrom; or if desired 24 covery that the aforesaid. spent iron sludg such oxide can be employed dry as a buffing which heretofore-has been either dis-card's, :r polishin material or jewelers rou e. as valueless or, when the ore market condi- Though n employ sulfuric acid in the tions permitted, converted b furnacing to form of ordinary commercial acid or sludge iron sinter, is admirably a apted for acid of the proper concentration, it is OlOVl- 25 production of ahigh grade oxide of in one without departing from the spirit at which is capable of serving as a buffing or of n vinv'ention, it may he desirable toadd polishing material, paint pigment or quantities of other acids depending ers rouge. I is character ofthe product desired, as

In carrying out my invention ll "5 id if present in small quantities'would Y,

W ably proceed as follows: i no prevent the transformation of the iron 85 l v A sufficient weight of concentrated sulfuric. sludge to a mixtureconsisting essentially of acid between 50 and 70 B.,for example ferric and ferrous sulfates.

66 Be, isgradually addedfi n a suitable Having thus described my invention, what mixing apparatus, to spent iron sludge claim and v desire to secure by Letters- 'fificonvert' the same into a substantially dry Patent of the United States is:

til

Mid

-'-' tially by the following equations:

' 'The decomposition of the said mixed sul fates occurs very readily,usually requiring ibut a ver few minutes, say five to ten '55 minutes. urt-hermore, the heaf d charge rather impure iron oxide, to the action; of a concentrated sulfuric acid of a ecific-gravj ity substantially exceeding 55 heating? the resultant sulfate compounds to 8 811 v ciently elevated temperature and' forasufi eient time to decompose the same into oxyl sulfur-acid gases andiron oxideand'sepaarately recovering such iron oxide.

3. The process which consists in subjecting magnetic iron sludge, comprising essen tially rather impure iron oxide, to the action of concentrated sulfuric acid sufficient to convert the same into a substantially d mixture consistinglessentially of ferrous an ferric sulphates, heating the resultant sulfate compounds to a sufiiciently velevated temperature and for a sufficient time to decompose the same into oxy sulfur-acid gases and iron and separately recovering such iron oxide. I

4. The process which consists in subjecting iron sludge, comprising essentially rather impure iron oxide, to the action of substantially a combining weight of concentrated sulfuric acid of a specific ravity substantially exceeding B., heating the resultant sulfate compounds to a sulliciently elevated temperature -and for a sufficient time to decompose thesame'into oxy sulfur-acid gases and iron oxide and separately recovering such iron oxide.

5. The process which consists in subjecting iron sludge, comprising essentially rather impure iron oxide,'to the action of substantially a combining weight of concentrated sulfuric acid of a specific gravity substantially exceeding B., heating the resultant sulfate compounds to a suficiently elevated temperature and for a suficient time to decompose the same into oxy sulfur-acid gases and iron oxide and separately recovering such iron oxid.

6. The process whichconsists in subjecting iron sludge, comprising essentially rather impure iron oxide, to the action of substantially a combining weight of concentrated sulfuric acid of a specific gravity substantially ranging between and B., heating the resultant sulfate compounds to a suiiiciently elevated temperature and for a suflicient time to decompose the same into oxy sulfur-acid gases and iron oxide and separately recovering such iron oxide.

7. The process which consists in subjecting iron sludge comprising essentially iron oxide to the action of concentrated sulfuric acid suflicient to convert the same into a substantially dry mixture consisting essentially of ferrous and ferric sulphates, heating the resultant sulfate compounds to a Suficiently elevated temperature and for a sulficient time to decompose the same into volatile oxy-sulfur compounds and iron and separately recovering such iron oxide.

Signed at New York city, in the county of Bergen and State of New York this 23rd. day of December, 1919.

CHAS. V. BACON. 

